The schwarz-weiß-rot flag (black-white-red) was adopted by the North-German Union in 1867, as a combination of the black-white of Prussia and the red-white of the Hanseatic League. In 1871 it was adopted as flag of commerce for the German Reich, and in 1892 promoted to national flag. The war flag (Kriegsflagge) from 1867 to 1921 was a white field, a black cross with in its middle a round escutcheon with the Prussian eagle, and the dexter chief quarter the black-white-red flag with an Iron Cross.
In 1919 the black-red-gold flag was adopted but as a compromise the black-white-red remained with a canton bearing the black-red-gold as commerce flag (and the war flag was the same plus an Iron Cross in the middle). The Nazis eliminated the red-black-gold in 1933 but continued to use the black-white-red (without the canton) as national and commerce flag until Sept. 15, 1935, when the more familiar Nazi flag was adopted uniformly (the war flag being a red field, black cross with swastika in the middle and Iron Cross in dexter chief.
So there is a connection between the black-white-red flag and the Nazis, since they re-introduced it as national flag in 1933. (Source: Brockhaus Encyclopedia).
Last modified: Oct 15, 1997